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// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;

public static class YieldReturn
{
    public static IEnumerable<string> SimpleYieldReturn()
    {
        yield return "A";
        yield return "B";
        yield return "C";
    }

    public static IEnumerable<int> YieldReturnInLoop()
    {
        for (int i = 0; i < 100; i++)
        {
            yield return i;
        }
    }

    public static IEnumerable<int> YieldReturnWithTryFinally()
    {
        yield return 0;
        try
        {
            yield return 1;
        }
        finally
        {
            Console.WriteLine("Finally!");
        }
        yield return 2;
    }

    public static IEnumerable<int> YieldReturnInLock1(object o)
    {
        lock (o)
        {
            yield return 1;
        }
    }

    public static IEnumerable<int> YieldReturnInLock2(object o)
    {
        lock (o)
        {
            yield return 1;
            o = null;
            yield return 2;
        }
    }

    public static IEnumerable<string> YieldReturnWithNestedTryFinally(bool breakInMiddle)
    {
        Console.WriteLine("Start of method - 1");
        yield return "Start of method";
        Console.WriteLine("Start of method - 2");
        try
        {
            Console.WriteLine("Within outer try - 1");
            yield return "Within outer try";
            Console.WriteLine("Within outer try - 2");
            try
            {
                Console.WriteLine("Within inner try - 1");
                yield return "Within inner try";
                Console.WriteLine("Within inner try - 2");
                if (breakInMiddle)
                    yield break;
                Console.WriteLine("End of inner try - 1");
                yield return "End of inner try";
                Console.WriteLine("End of inner try - 2");
            }
            finally
            {
                Console.WriteLine("Inner Finally");
            }
            Console.WriteLine("End of outer try - 1");
            yield return "End of outer try";
            Console.WriteLine("End of outer try - 2");
        }
        finally
        {
            Console.WriteLine("Outer Finally");
        }
        Console.WriteLine("End of method - 1");
        yield return "End of method";
        Console.WriteLine("End of method - 2");
    }

    public static IEnumerable<string> YieldReturnWithTwoNonNestedFinallyBlocks(IEnumerable<string> input)
    {
        // outer try-finally block
        foreach (string line in input)
        {
            // nested try-finally block
            try
            {
                yield return line;
            }
            finally
            {
                Console.WriteLine("Processed " + line);
            }
        }
        yield return "A";
        yield return "B";
        yield return "C";
        yield return "D";
        yield return "E";
        yield return "F";
        // outer try-finally block
        foreach (string line in input)
            yield return line.ToUpper();
    }

    public static IEnumerable<Func<string>> YieldReturnWithAnonymousMethods1(IEnumerable<string> input)
    {
        foreach (string line in input)
        {
            yield return () => line;
        }
    }

    public static IEnumerable<Func<string>> YieldReturnWithAnonymousMethods2(IEnumerable<string> input)
    {
        foreach (string line in input)
        {
            string copy = line;
            yield return () => copy;
        }
    }

    public static IEnumerable<int> GetEvenNumbers(int n)
    {
        for (int i = 0; i < n; i++)
        {
            if (i % 2 == 0)
                yield return i;
        }
    }

    public static IEnumerable<char> YieldChars()
    {
        yield return 'a';
        yield return 'b';
        yield return 'c';
    }
}